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For One and All,
Next - Part # 2 of "The Simplest Shortwave Listener (SWL) Antennas That I Know Of..." - The Same Idea Taken In-Side {In-Doors} and Guess What . . . It Is Ready Made ! http://groups.yahoo.com/group/Shortw...a/message/9929 One again this simple Antenna is a form of a Doublet {Dipole} Antenna but it is much smaller and can be used as an In-Door Antenna for Shortwave Listening. IT IS THE FM FOLDED DIPOLE ANTENNA - ? WHAT ? Hey - That is too short and small for a Shortwave Antenna ! Well Yeah and so is the Whip Antenna that is built into every 'portable' AM / FM Shortwave Radio. When putting an Antenna {Any Antenna} In-the-Room is all you can do; and making an Antenna yourself is not an option; and you Antenna Budget is under $5. You are limited in just 'what' you can do for an Antenna and your Antenna choices. WHAT - Is very common and available and cheap that is Ready-Made and can be used as a Antenna for Shortwave Listening (SWL) with : * Most 'portable' AM / FM Shortwave Radios with an 1/8" Mono-Jack External Antenna Input -How- Remove the Antenna Terminals and connect the Antenna Wires to an 1/8" Mono Plug and plug that into the Radio. * Shortwave Receivers with HI-Z 500 Ohm Antenna Terminals. -How- Connect the Antenna Terminals to the Receiver. RIGGING - Tape and Thumb-Tacks will hold it in place. SOURCES - Folded Dipole Antenna for FM Radio RadioShack Catalog # 42-2385 http://www.radioshack.com/product/in...ductId=2062691 * Horizontal Arms Tip-to-Tip 58-60 Inches across * Vertical Feed-in-Line 72 Inches long IMAGE = http://tinyurl.com/melg5 IMAGES = http://tinyurl.com/m2qaz Alternative Links = http://tinyurl.com/pfvcr http://tinyurl.com/rkcro http://tinyurl.com/pldul http://tinyurl.com/n76xa eBay FM Dipole Antenna = http://tinyurl.com/mzoth BUT BUT BUT ! - IT'S TOO SHORT FOR SHORTWAVE ! YES - That is Right - So for Shortwave use this FM Folded Dipole Antenna is simply a Bent-Thin-Compresed Random Wire Antenna that terminates to itself effectively forming a Loop. - What Again ? - Well it is not 'cut' for any Shortwave Frequency and will be used across the Shortwave Bands : So it "IS" a Random Wire Antenna for this application. - Why Is It A Loop ? - The FM Folded Dipole Antenna is connected to {Starts at} one side of the Radio's Antenna Input and is also is connected to {Ends at} the other side of the Radio's Antenna Input forming a Bent-Thin-Compressed Loop. - Little But Long - What really matters is that at : 72" Out + 30" Out + 60" Across + 30" In + 72" In = 264" which adds-up-to 22 Feet of Wire in the FM Folded Dipole Antenna - And Hey one of those Reel {Roll-Up} Portable Shortwave Antennas has about 23 Feet of Wire in them. - Bigger than the Whip - Most Whip Antennas that are built into the average 'portable' AM / FM Shortwave Radios are about 28" to 42" long and very thin. If you wanted to assign them an Area-of-Space that they occupied it would be rather small 1" X 28"-42" = 28-42 Square Inches. -But- Now the FM Folded Dipole when it is layed-out on a Wall in the "T" Shape actually defines a Triangle 60" Across the Top with a Vertical Demension of 72" = 2160 Square Inches. The FM Folded Dipole clearly has a greater Signal Capture Area then the Whip Antenna. FWIW - The simplest In-Door Antenna is the Folded Dipole. http://www.kqed.org/help/radio/radio-tips.jsp The Folded Dipole Antenna is frequently packed with new AM/FM Radios. It is fabricated from Flat Television Antenna Lead-in Material (often called Twin-Lead). Twin-Lead is the Flat Plastic-Covered Wire - usually Brown or pinkish-clear in color. A Folded Dipole Antenna is in the Shape of the Letter "T". The Horizontal Part (the Arms) of the Letter is the actual Antenna. The Vertical Part (the fee-in-line) of the Letter connects the Antenna to the Radio/Receiver. Most often the Folded Dipole Antenna is placed on a Wall with the Vertical feed-in-line going straight-up the Wall; and both of the Arms Stretched-Out in opposite directions Horizontally. Again looking like a "T". Experiment - Try orienting the Arms of the Dipole in different positions for best Reception. Sometimes best results may be obtained when the Arms are Vertical or Sloping. Often, the Antenna can be Taped or Thumb-Tacked to the Wall or to the back of Furniture when a good location is found. TIP - Placing the Antenna in front of a Window or Diagonally across a Window often is a good location for the best Radio Reception. A Simple, Efficient TV Antenna http://www.wfu.edu/~matthews/misc/dipole.html "How To" - Make a Folded Dipole from Twin-Lead http://www.kyes.com/antenna/antennatypes/twinlead.jpg Note - Folded Dipoles can be made very small ![]() http://users.skynet.be/chricat/anten...d-dipole-z.jpg General Dipole Antenna Info - Links http://en.wikipedia.org/wiki/Dipole_antenna http://www.cebik.com/vhf/fm1.html http://www.qsl.net/w4sat/fdipole.htm SUMMARY - The FM Folded Dipole Antenna Easy-to-Build and Cheaper-to-Buy -and- for a simple 'passive' In-Door Shortwave Antenna - It Works ! Keeping It Simple And Practical - iane ~ RHF |
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